(For the latest Human Nature columns on obesity, genital mutilation, and living death, click here.)
Bicycle helmets may backfire by encouraging cars to drive closer to the cyclist. Theory: Wearing a helmet makes you look like you know what you're doing, so drivers assume you can operate in tighter space. Evidence: A traffic psychologist rode a sensor-equipped bike around Britain, and when he wore a helmet, cars passed more than three inches closer, on average, than when he didn't. He was also hit by two vehicles while wearing the helmet. Bonus finding: When he dressed as a woman, drivers gave him more than five inches of extra space. Psychologist's interpretation: Helmets protect you in a low-speed tumble but may backfire in serious car traffic. Accident-prevention group's rebuttal: Wear your helmet, and we'll educate drivers to give you more space. (For Human Nature's update on the dangerous distraction of car navigation systems, click here.)
The first man and woman to get "bionic" arms demonstrated the devices. After losing your arm, your brain thinks the nerves that went to the arm still operate it. Surgeons attach the stumps of these nerves to expendable muscle in your chest. Then they wire the muscle to your prosthetic arm by electrodes. Result: When your brain tells the arm to move, the chest muscle twitches, and the electrodes make the arm move. The Department of Defense is funding the technology. Approved spin: This will be great for the 400 soldiers who lost limbs in Iraq. Unapproved spin: or we could just pull out and let soldiers keep the arms they were born with. (For Human Nature's previous update on prosthetic limbs, click here. For military-funded sensory enhancement devices, click here.)
Anecdotal reports suggest Ambien can awaken brain-damaged people from prolonged unresponsiveness. One patient had been unresponsive for two years; another for five years. Both became aware and began speaking. According to the Guardian, "Many stroke victims, patients with head injuries and those whose brains have been deprived of oxygen, such as near-drowning cases, have reported significant improvement in speech, motor functions and concentration after taking the drug." A study to test the effect is about to begin. Hypothesis: Damaged brains can "hibernate," altering receptors so that Ambien aborts the hibernation. Skeptical reactions: 1) Let's wait for the study. 2) Even if the drug helps these folks, they may go back under like the patients in Awakenings. (For Human Nature's take on the nightmare of being trapped in a pseudo-vegetative state, click here. For updates on Ambien and sleep-driving, click here, here, here and here.)
Michigan legislators proposed mandatory vaccinations of sixth graders for a sexually transmitted disease. The vaccine blocks human papilloma virus (HPV) infections, which can cause cervical cancer, which kills 3,700 American women each year. Argument for the proposal: This is a cancer we can wipe out through vaccination. Arguments against it: 1) This is an STD, so kids can avoid it by abstaining from sex. 2) Vaccinating all girls sends a message that sex is OK. 3) Making the vaccine mandatory, even with an opt-out clause, violates parents' rights. (For a previous update on HPV and mouth cancer, click here. For Human Nature's take on the HIV risks of oral and anal sex, click here.)
Men are programmed for war, according to a scientist whose study will appear soon in Psychological Science. In a money game, men increased their cooperation (potentially at each one's expense) more than women did when participants were told that they were competing collectively against a rival group. Additional evidence: 1) "Men are more likely to support a country going to war." 2) "Men are more likely to lead groups in more autocratic, militaristic ways." 3) Male chimps don't often cooperate, but "they go out on raids into … and kill off members of rival groups.'' Anti-male spin: War among men is "inevitable," and the solution is to elect more women. Alternative anti-male spin: Men don't even like war; they just do it to show off. Pro-male spin: We don't just fight; we fight cooperatively. (For Human Nature's take on men, women, and aggression, click here.)
The U.S. House voted to ban the slaughter of horses for meat. Arguments for the ban: 1) Unlike cattle, "horses are American icons." 2) "They're as close to human as any animal you can get." 3) They're like pets. 4) They're smart, hardworking, and good companions. 5) Our treatment of them reflects our "core values." Arguments against it: 1) Keeping useless horses alive is too expensive. 2) If we don't let owners "process" their horses, they'll leave the poor beasts to suffer and die slowly. 3) If we don't slaughter the horses, Mexican and Canadian plants will take our market share. 4) If we let the gummint ban horse slaughter, next it'll mess with the beef, pork, and poultry bidness. (For Human Nature's take on horses and animal slaughter, click here.)
Brain scans suggest a woman diagnosed as "vegetative" is actually conscious. Evidence: "When asked to imagine playingtennis or moving around her home, the patient activated predictedcortical areas in a manner indistinguishable from that of healthyvolunteers." Pro-life spin: Terri Schiavo was murdered! Skeptical reactions: 1) This woman showed signs of minimal consciousness within a year; Schiavo suffered far worse brain damage and showed no consciousness for 15 years. 2) Nobody in a persistently vegetative state for two years has been shown to recover awareness. 3) Don't use this case to raise false hopes for families of PVS patients. Moderate reactions: 1) We'd better rethink our practice of judging people by their ability to communicate. 2) Give them all brain scans. (For Human Nature's takes on the Schiavo case, click here, here, and here.)
A new drug delays premature ejaculation. The drug, an SSRI called dapoxetine, was tried on a sample of men who previously ejaculated, on average, less than one minute after vaginal penetration. A moderate dose delayed ejaculation to 2.78 minutes; a double dose delayed it to 3.32 minutes. Bonus finding: A placebo doubled average endurance to 1.75 minutes. Downside: "Side effects of the drug included nausea, diarrhea, headache and dizziness." Old medical spin: By preventing ejaculation, SSRIs emasculate men and harm sexual relationships. New spin: By preventing ejaculation, SSRIs empower men and improve sexual relationships. (For Human Nature's previous update on an anti-ejaculation cream, click here.)
Aging may be nature's way of preventing cancer. A gene that inhibits cancer appears to do so by preventing adult stem cells from multiplying. As you age and become more cancer-prone, the gene makes multiplication harder and harder. Result: Your body stops repairing itself, and you die. The good news: Aging isn't inevitable wear and tear. The bad news: Aging is programmed, and if we block the program, we'll get cancer. Optimistic spin: Maybe we can avoid both by learning to switch the program off and on. Political spin: Adult stem cells will never be as effective as embryonic stem cells. (For Human Nature's takes on the stem-cell debate, click here, here, here, and here.)
Midlife divorce increases heart disease for women but not men. Based on several thousand cases beginning at age 51, researchers calculated that by age 60, women who were divorced, remarried, or widowed were nearly 50 percent more likely to have cardiovascular disease than women who stayed married. "No such difference was seen for men. In fact, men who remarried were actually 19% less likely to develop heart disease than those who had stayed married to the same person." The authors conclude that "emotional distress and socioeconomic status" cause the harm to women. (Economics can't account for the whole effect, since "remarried women were more likely to have heart disease than continuously married women, although their financial circumstances were not substantially worse.") Feminist spin: Men have no hearts. Anti-feminist spin: We're just happier without you.
Latest Human Nature columns: 1) Buried alive in your own skull. 2) The global explosion of fat. 3) The case for genital mutilation. 4) The liquid world of terrorism. 5) The deluded bubble of air conditioning. 6) Prophets of a post-human race. 7) Stop killing meat and start growing it. 8) The creeping logic of embryo weeding. 9) The war on tanning.